MAN marine engines we service
Our diesel technicians work across the MAN marine range — propulsion and auxiliary — for both pleasure and commercial vessels.
Model not listed? Call us on (03) 9399 5888 — we almost certainly cover it.
Common MAN issues we diagnose & fix
Sound familiar? These are the symptoms owners most often describe when they call us about MAN i6, V8 and V12 marine diesels — almost all of them normal service items on a hard-working engine, and all of them things we diagnose and repair every week.
Down on power, black smoke at full throttle
The charge-air cooler on these engines is seawater-cooled, and a fouled or corroded core is a common culprit — airflow drops, exhaust temps climb and the engine can't reach rated revs. We strip, clean and pressure-test the cooler before corrosion lets seawater anywhere near the intake.
Hard starting, rough idle or grey smoke
Injectors are precision components and a known service item on higher-hours engines, particularly where fuel quality has been marginal. We inspect the fuel system, have suspect injectors tested, and replace what's worn before it can do further harm.
Overheating at cruise revs but fine at idle
This classic pattern usually points to the raw-water side — a tired impeller, fouled heat-exchanger or cooler cores, a blocked strainer or spent anodes restricting flow. We test flows and temperatures across the whole cooling circuit to find the restriction.
Raw-water pump weeping or dripping
A drip from the pump's telltale hole is the early warning that a shaft seal is on its way out — a routine wear item, but left alone it can put seawater into places it should never reach. We rebuild or replace pumps before they cause real damage.
Surging, hunting or losing power under load
Often traced to fuel restriction — blocking filters, diesel bug or water in the tanks. We work through the fuel supply from the tank pickup forward and sort the contamination at its source.
Recognise one of these? Call (03) 9399 5888 or book a diagnostic — we'll find the cause before it becomes a haul-out.
Our MAN marine services
MAN Servicing & Scheduled Maintenance
Regular servicing is the cheapest insurance you can buy for a high-output MAN diesel, and our experienced technicians service all MAN marine engines to manufacturer-recommended intervals. We tailor each service to how your i6, V8 or V12 is actually used — leisure cruising, charter or hard commercial duty — so wear items are caught before they become breakdowns. Book a scheduled service and we will keep clear records for your logbook, insurer and future resale.
- Oil and filter changes, fuel and air filter replacement to MAN intervals
- Coolant, belt, impeller and anode inspection and renewal
- Valve clearance checks and top-end inspection on i6, V8 and V12 engines
- Service-history records for survey, insurance and resale
Diagnostics & Fault-Finding
When a MAN isn't running right, guesswork gets expensive. We troubleshoot symptom-first — overheating, hard starting, smoke, power loss, vibration — methodically testing the cooling, fuel-supply, air and exhaust systems to find the real cause. You get a clear explanation of what is wrong and a fixed quote before any work proceeds.
- Cooling system pressure, flow and temperature testing
- Fuel supply and filtration checks, from tank to lift pump
- Air intake, turbo boost and exhaust restriction checks
- Smoke, power-loss, overheating and vibration investigation
Repairs, Overhauls & Rebuilds
From a single injector to a complete engine, we carry out mechanical repairs, top-end work and full overhauls on MAN marine diesels. Whether it is cooling, fuel, turbo or injection trouble, we repair the cause properly rather than patching the symptom. When an engine is tired, we will give you a straight assessment of rebuild versus replacement so you can spend your money where it counts.
- Top-end and full engine overhauls and rebuilds
- Cooling system, heat exchanger, raw-water and head-gasket repairs
- Fuel system, injector, high-pressure pump and turbocharger work
- Honest rebuild-vs-replace and repower assessments
Parts, Repower & Installation Support
We source genuine MAN parts and quality aftermarket components to suit your budget and how long you plan to keep the boat. If your MAN is beyond economical repair, we provide impartial repower advice and support engine installation, alignment and commissioning. As authorised dealers for Volvo Penta, Yanmar, Twin Disc and ZF, we can also talk through repower options and supply matched gearboxes.
- Sourcing of genuine and quality aftermarket MAN parts
- Filters, impellers, belts, sensors and service kits
- Repower advice, engine installation, alignment and commissioning
- Matched gearbox supply as authorised Twin Disc and ZF dealers
Mobile Service, Commercial & Survey Support
Some jobs are easier done where the boat sits, so we offer mobile service to marinas and moorings across Port Phillip Bay, with larger work handled at our Spotswood workshop. We support commercial operators and owners preparing for survey with inspections, fault rectification and clear documentation. Pre-purchase and insurance inspections give you an independent, expert view of a MAN engine's true condition before you buy or renew cover.
- Mobile service and breakdown response across Port Phillip Bay
- Pre-purchase and insurance condition inspections
- Commercial fleet servicing and survey-preparation support
- Workshop overhauls for major repairs and rebuilds
Vessels & applications we look after
Get a MAN service quote
Tell us your model and the issue — workshop or mobile across Port Phillip Bay, usually back to you in 1 business day.
Why boat owners choose Mariner
MAN marine service — your questions answered
Do you service MAN marine engines even though you are not a MAN dealer?
Yes. Mariner Engineering is an independent marine workshop and our diesel technicians service, diagnose, repair and rebuild MAN marine engines every day. We are not a factory-authorised MAN dealer, but we have the diagnostic equipment, experience and parts access to look after your i6, V8 or V12 properly. Call (03) 9399 5888 to discuss your engine.
Can you get parts for MAN marine engines?
Yes. We source genuine MAN parts as well as quality aftermarket components, and we will recommend the right option for your budget and how long you plan to keep the boat. Common service items such as filters, impellers, belts and sensors are readily available. For less common parts we will confirm availability and lead time up front when we quote.
Do you offer mobile service for MAN engines around Port Phillip Bay?
Yes. We provide mobile service to marinas and moorings across Port Phillip Bay for servicing, diagnostics and many repairs. Larger jobs such as overhauls and rebuilds are best done at our Spotswood workshop where we have the tools and lifting gear. Call (03) 9399 5888 and we will work out whether your job suits a mobile visit or a workshop booking.
Should I rebuild my MAN engine or replace it?
It depends on hours, overall condition and how long you intend to keep the vessel. We will assess the engine honestly and give you the real cost of a rebuild against a repower, so you can make an informed decision. As authorised dealers for Volvo Penta, Yanmar, Twin Disc and ZF, we can also map out repower options if replacement makes more sense. Book an inspection and we will give you a clear recommendation.
How quickly can you turn my MAN engine around?
Routine servicing and many diagnostic jobs can usually be scheduled quickly, while overhauls and rebuilds depend on parts lead times and the scope of work. We will give you a realistic timeframe when we quote and keep you updated throughout. For urgent breakdowns, call (03) 9399 5888 and we will prioritise getting you back on the water.
Request a MAN service or repair quote
Tell us your MAN engine model, your vessel and the service, fault or rebuild you need, and our team will get back to you with a quote — usually within 1 business day.
Mariner Engineering is an independent marine service and repair provider and is not an authorised dealer of, or affiliated with, MAN. MAN and associated model names are trademarks of their respective owners, used here only to describe the engines we service.